Prior art of possible relevance includes U.S. Pat. Nos. 2,317,519 issued Apr. 27, 1943 to Coons and 3,495,657 issued Feb. 17, 1970 to Keith.
Many heat exchangers employ cores constructed of multiple tubes which in turn are provided with segmented external fins, such fins, because of their segmentation, appearing as radially outwardly extending spines. The tubes carry a heat transfer medium subject to heating or cooling by the flow of a fluid, most typically air, across the fins and the tubes. The overall heat transfer coefficient of such structures is largely controlled by the air or fluid side heat transfer coefficient and the effective air side area over which heat transfer may occur.
When air or fluid flows across a row or rows of externally finned tubes, recirculation zones are formed on the downstream side of the tubes. These recirculation zones are areas of relatively low localized air velocity with the consequence that the air side heat transfer coefficients in such areas are relatively low and the finned heat transfer area in such zone is not utilized effectively.
Where such external fins are segmented, there is an increase in the resistance to air flow. This in turn increases the size of the recirculation zone downstream of the tube and further decreases the local air velocity both upstream and downstream of the tube which further reduces the effective heat transfer area of the finned surface. The ultimate result is poor material utilization for heat transfer on both the extreme upstream and downstream sides of the fin tube. The underutilized material used in forming the fins additionally makes the heat exchanger both larger and more costly than is necessary.
The present invention is directed to overcoming one or more of the above problems.